Method for determining whether internal negative plate of lithium battery has material drop

Abstract

The invention provides a method for determining whether the internal negative plate of a lithium battery has material drop, which includes the following steps: (1) pre-charging a lithium battery for the first time, testing the AC internal resistance of the lithium battery pre-charged for the first time, and recording the internal resistance as an internal resistance I; (2) carrying out cyclic charging and discharging on the lithium battery pre-charged for the first time in step (1) for three times, and at the end of three times of cyclic charging and discharging, testing the AC internal resistance of the lithium battery, and recording the internal resistance as an internal resistance II; and (3) calculating the internal resistance difference, and comparing the internal resistance difference with a standard internal resistance difference to determine whether the internal negative plate of the lithium battery has material drop, and determining that the internal negative plate of the lithium battery has material drop if the internal resistance difference is greater than or equal to the standard internal resistance difference. The method has the advantage that whether the internal negative plate of a lithium battery has material drop can be determined quickly without disassembling the lithium battery, namely, a normal lithium battery and a lithium battery with material dropping from the internal negative plate can be distinguished. The method is easy to operate, is simple and effective, and can save a lot of time and improve the work efficiency.

Description

Technical field [0001] The present invention relates to the technical field of lithium-ion batteries, and in particular to a method for judging that the negative electrode sheet inside the lithium battery is missing. Background technique [0002] Lithium-ion batteries have been widely used in digital and communication products such as portable computers, portable music players, and mobile phones due to their large specific energy, high working voltage, long cycle life, no memory effect, and green safety. in. This year, applications in the fields of electric vehicles, aerospace satellites, weaponry, power tools, and various energy storage devices have also shown good prospects. [0003] Lithium batteries inevitably appear material and powder drop during the assembly process. Due to the relatively small adhesion between the negative electrode material and the copper foil, the negative electrode material is more likely to drop from the foil material. At present, it is necessary to o...

AI Technical Summary

Problems solved by technology

Due to the falling of the negative electrode inside the battery, when the battery is charging, there is no carbon layer with a sheet structure for lithium ions to be inserted, and metal lithium ions will be deposited on the surface of the bare copper foil. The deposited lithium ions first undergo a reduction reaction on the surface of the copper foil. Destroy the oxidation protective layer on the surface of copper foil; correspondingly, the potential of the negative electrode decreases, and the potential borne by the copper foil current collector is low, and the electrolyte will inevitably undergo a reduction reaction on the exposed surface of the copper foil current collector, which will easily lead to electrolyte and copper without an oxide layer Foil direct contact, copper foil negative electrode corrosion fracture

Images